The present invention relates to a compact, self-contained, low-cost, integrated, disposable and personal emergency breathing system for breathing filtered air in toxic gas or smoke-filled environments.
Personal breathing systems for use in emergency situations, for example, in toxic gas or smoke-filled environments, have been designed and constructed in the past. For example, in each of my prior U.S. Pat. Nos. 5,186,165 and 5,315,987, the disclosures of which are incorporated by reference, there is provided a canister containing a filtration unit, a hood, and a mouthpiece, the canister also including a closure for containing the hood, mouthpiece and filtration unit within the canister in an unused but ready-for-use condition. Upon removal of the closure and deployment of the mouthpiece and hood from the canister, the individual may don the hood by pulling the hood over the individual""s head and locate the deployed mouthpiece in his/her mouth. The canister remains attached to the mouthpiece and hood and is supported by the individual by the mouthpiece. By breathing filtered air, the individual may escape from the toxic gas or smoke-filled environment.
In one form, a tab is removable from the bottom of the canister to expose apertures to ambient air whereby ambient air is supplied to the filtration unit and filtered air is provided to the individual for breathing through the mouthpiece. In another form, the removal of the closure not only permits deployment of the hood and mouthpiece but also exposes an inlet into the canister so that ambient but toxic gas or smoke-filled air is passed axially through the filtration unit so that the individual can breathe filtered air. Canisters of this type have been eminently successful and have enabled individuals to escape environments filled with smoke or toxic gases.
In accordance with a preferred embodiment of the present invention, there is provided a similar type of personal compact breathing system, including a canister containing a filtration unit, a hood and a mouthpiece wherein the filtration unit is specifically configured to have an increased mass of filtration material and a reduced pressure drop. As in the prior systems, the hood and mouthpiece are deployable from the canister upon removal of the closure. In accordance with an aspect of the present invention, however, the filtration unit is provided in an annular configuration. The annular filtration unit defines with the interior walls of the canister an annular passage about the filtration unit. The inner and outer walls of the filtration unit have apertures for passing ambient air received within the annular passage about the filtration unit in a direction generally radially inwardly of and through the filtration unit. The filtration unit also includes a central passageway for directing the filtered breathable air axially away from the filtration unit and into the mouthpiece.
Additionally, the annular passage about the filtration unit includes an annular filter in communication with an air inlet into the canister. Particularly, and in a preferred embodiment, the air inlet is exposed to receive ambient air upon removal of the closure. The filter in the annular passage is closed at one end and open at its opposite end to receive the ambient air from the air inlet whereby air passes through the filter for passage radially inwardly through the filtration unit and into the central passageway. The filtration unit also includes interior linings along the inner and outer walls to confine the particulate material of the filter and any fines of, for example, activated charcoal, within the annular unit.
The end of the filtration unit adjacent the lower end of the canister includes a cap and annular resilient material along an inside surface of the cap facing and in registration with the particulate material in the filtration unit. The resilient material maintains the particulate material in a compacted or compressed condition within the filtration unit, avoiding settling. Also, an annular rib or rim is carried by the end cap as well as by an annular ring of the opposite end of the filtration unit to preclude channeling or air bypass about the filtration material.
In a further embodiment of the present invention, a monolith filter is provided for converting carbon monoxide to carbon dioxide by a catalyzation process. The monolith filter overlies the upper annular end of the filtration unit and defines an annular plenum therewith. The tube defining the central passage terminates below the monolith filter and above the end of the annular filtration unit to define an annular plenum. As a consequence, filtered air from the first filter passes through the disk-like monolith filter from the plenum and from the central tube. The monolith filter is a ceramic substrate dipped in precious metals, such as palladium or platinum.
In a preferred embodiment according to the present invention, there is provided a personal emergency breathing system comprising a canister having an opening and a closure removably carried by the canister for closing the opening, a generally annular air filtration unit within the canister containing air filtering material and defining with the canister an annular passage about the filtration unit for receiving ambient air from an air inlet to the canister, the filtration unit having an axially extending central passageway and inner and outer walls with apertures enabling transmission of ambient air in a generally radial direction from the annular passageway through the walls and filtering material and into the central passageway, a mouthpiece carried by the canister in communication with the central passageway for receiving filtered air from the central passageway and deployable from the canister, a hood carried by the canister enveloping the mouthpiece and deployable from the canister, the hood having an opening for receiving an individual""s head and neck whereby the hood, when deployed from the canister, may envelop an individual""s head, the mouthpiece and the hood being disposed in a collapsed condition in the canister adjacent the canister opening and between the filtration unit and the closure whereby, upon removal of the closure from the opening, the hood and the mouthpiece are deployable from the canister through the canister opening to a location external to the canister, with the mouthpiece in communication with and receiving filtered air from the filtration unit.
In a further preferred embodiment according to the present invention, there is provided a personal emergency breathing system comprising a canister having an opening and a closure removably carried by the canister for closing the opening, a generally annular air filtration unit within the canister containing air filtering material and defining with the canister an annular passage about the filtration unit for receiving ambient air from an air inlet to the canister, the filtration unit having an axially extending central passageway and inner and outer walls with apertures enabling transmission of ambient air in a generally radial direction from the annular passageway through the walls and filtering material and into the central passageway, a plenum in the canister for receiving the filtered air from the central passageway, a secondary filter for receiving the filtered air from the plenum and further filtering the air, a mouthpiece carried by the canister in communication with the secondary passageway for receiving the further filtered air and deployable from the canister, a hood carried by the canister enveloping the mouthpiece and deployable from the canister, the hood having an opening for receiving an individual""s head and neck whereby the hood, when deployed from the canister, may envelop an individual""s head, the mouthpiece and the hood being disposed in a collapsed condition in the canister adjacent the canister opening and between the filtration unit and the closure whereby, upon removal of the closure from the opening, the hood and the mouthpiece are deployable from the canister through the canister opening to a location external to the canister, with the mouthpiece in communication with and receiving the further filtered air.